What is Truth?
- Any string is true except for "" and "0".
- Any number is true except for 0.
- Any reference is true.
- Any undefined value is false (implictly by first rule).
Truth is evaluated in a scalar context.
What is the truth of a list?
There is no perl opeartion that will return a list
in a scalar context, they all return a scalar value instead.
|
Examples:
| 0 | # would become the string "0",
so false |
| 1 | # would become the string "1",
so true |
| 10 - 10 | # 10-10 is 0, becomes the string "0",
so false |
0.00 | # becomes 0, converts to string "0",
so false |
| "0" | # the string "0",
so false |
| "" | # the null string,
so false |
| "0.00" | # the string "0.00", neither empty nor
exactly "0", so true |
| "0.00" + 0 | # the number 0 (coerced by the +),
so false |
| \$a | # a reference to $a, so true,
even if $a is false |
| undef() | # a function returning the
undefined value, so false |
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